Unix Tools

There are a wide variety of Unix command line tools and techniques
which are simply not available to average Windows users. These
techniques can be extraordinarily powerful. Most involve automating
tasks that Windows users do tediously by hand, would buy expensive
software to do, or would hire out to someone else who would use UNIX
to do them. Windows users often don't realize that computer systems
can do such wonderful time saving things.

A few examples:

The GIMP or
ImageMagick can automatically
process a large set of images without ANY user interaction. Smooth,
sharpen, resize, convert, rotate, or color balance consistently while
you drink coffee. This is a major boon to graphics designers, web site
designers, or anyone writing reports with graphics.

Apache can serve your web pages
for you like it does 90% of the rest of the Internet.

Besides a plethora of out of the box tools for automation, and a
highly reliable architecture, there are UNIX specific techniques for
programming which are powerful and integrate well. Go to
The Art of Unix
Programming for Eric Raymond's opinions on what makes UNIX
programming techniques so powerful.